mudtrucker wrote:In general how much lift can you have with a solid flat tappet cam without going to extreme duration?

You better define EXTREME duration. Max lift and flank velocity are the limitations of a flat tappet lobe given the diameter of the lifter. The limitations of a roller lobe are it's maximum acceleration and minimum intensity which can be achieved; again given the diameter of the lifter wheel.

RACER RED wrote:IDT 572, You mentioned the mushroom lifters and bull nose cam, where can you buy these items and what are you calling pricey? Thanks for help. Dave

They will cost more than a typical roller set-up...... I haven't seen any mushroom lifters for a long time but the custom cam cores can start at about $500-800+ depending on how many you want and if they are common or not.

dfree383,Thanks for the response. Well that certainly is a bit pricey,especaily with the extra machineing invovled. Certainly not a cost effective approach the getting more lift under the curve. I dont want to run solid rollers on the street but want to get as much lift as possible to feed a big cu in motor.Thanks again.

RACER RED wrote:dfree383,Thanks for the response. Well that certainly is a bit pricey,especaily with the extra machineing invovled. Certainly not a cost effective approach the getting more lift under the curve. I dont want to run solid rollers on the street but want to get as much lift as possible to feed a big cu in motor.Thanks again.

Those who are required to run flat tappet lifters because of rules get the lift they want by juggling the rocker arm ratios.

I ran mushroom tappets for years in Big Block drag race Mopars and there were no SPECIAL camshaft cores, (I believe the Chrysler "MINI EXPRESS" camshaft is still sold from the Mopar catalog), or extra machining to be done other than a bit of hand grinding on the block bulkheads near the lifter bores.

We ran them in small block Chevy short oval track engines for years also. The cores were regular cores but, the lobes were narrower and ground between them.

Like always I did not word my question properly and kinda got flamed and then it goes to hell talking about mushroom lifters that would cost three times as much as a roller lifter. I was simply asking how much lift can you get by with out going over say 270-275 @ .050 on a standard solid flat tappet. When does the ramp rate become to extreme for a solid flat tappet? I am looking to run a solid flat tappet in the .700ish range with around a 270-275 dur@.050,Flame away!!!!!!!

Last edited by mudtrucker on February 21st 2012, 5:18 pm; edited 1 time in total

.398 with a 1.8 rocker .716 before lash 270-275 @ .050 Comp has several lobes in this range and about 184 @ .200 low 300's @ .020 There are more aggressive but I normally stay around this for reliability.

I would run the EDM lifters with this lobe. And Higher spring pressures are required.

This is what I put in Mike Jaworskie's 528 in the build section, It made good power for a flat top flat tappet deal.

mudtrucker wrote:Like always I did not word my question properly and kinda got flamed and then it goes to hell talking about mushroom lifters that would cost three times as much as a roller lifter. I was simply asking how much lift can you get by with out going over say 270-275 @ .050 on a standard solid flat tappet. When does the ramp rate become to extreme for a solid flat tappet? I am looking to run a solid flat tappet in the .700ish range with around a 270-275 dur@.050,Flame away!!!!!!!

That's the main reason I said to explain your meaning of EXTREME duration. That term would not be near the same for everyone.

mudtrucker wrote:Like always I did not word my question properly and kinda got flamed and then it goes to hell talking about mushroom lifters that would cost three times as much as a roller lifter. I was simply asking how much lift can you get by with out going over say 270-275 @ .050 on a standard solid flat tappet. When does the ramp rate become to extreme for a solid flat tappet? I am looking to run a solid flat tappet in the .700ish range with around a 270-275 dur@.050,Flame away!!!!!!!

That's the main reason I said to explain your meaning of EXTREME duration. That term would not be near the same for everyone.